Privat tunel vpn

"VPN" redirects here. For other uses, see VPN (disambiguation).

A virtual private network (VPN) extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.

Applications running across a VPN may therefore benefit from the functionality, security, and management of the private network.[1]

VPNs privat tunel vpn allow employees to securely access a corporate intranet while located outside the office. They are used to securely connect geographically separated offices of an organization, creating one cohesive network.

Individual Internet users may secure their transactions with a VPN, to circumvent geo-restrictions and censorship, or to connect to proxy servers privat tunel vpn the purpose of protecting personal identity and location in order to stay anonymous on the internet. However, privat tunel vpn Internet sites block access to known VPN technology to prevent the circumvention of their geo-restrictions.

Therefore, many personal use Privat tunel vpn providers have been developing technologies to bypass the blocking of proxies.

A VPN is created by establishing a virtual point-to-point connection through the use of dedicated connections, virtual tunneling protocols, or traffic encryption.

A VPN available from the public Internet can provide some of the benefits of a wide area network (WAN). From a user perspective, the resources available within the private network can be accessed remotely.[2]

Traditional VPNs are characterized by a point-to-point topology, and privat tunel vpn do not tend to support or connect broadcast domains, so services such as Microsoft WindowsNetBIOS may not be fully supported or work as they would on a local privat tunel vpn network (LAN).

Designers have developed VPN variants, such as Virtual Private LAN Service (VPLS), and Layer 2 Tunneling Protocols (L2TP), to overcome this limitation.

These networks are not considered true VPNs because they passively secure the data being transmitted by the creation of logical data streams.[3] They have been replaced by VPNs based on IP and IP/Multi-protocol Label Switching (MPLS) Networks, due to significant cost-reductions and increased bandwidth[4] provided by new technologies such as Digital Subscriber Line (DSL)[5] and fiber-optic networks.

VPNs can be either remote-access (connecting a computer to a network) or site-to-site (connecting two networks).

In a corporate setting, remote-access VPNs allow employees to access their company's intranet from home or while travelling outside the office, and site-to-site VPNs allow employees in geographically disparate offices to share one cohesive virtual privat tunel vpn.

A VPN can also be used to interconnect two similar networks over a dissimilar middle network; for example, two IPv6 privat tunel vpn over an IPv4 network.[6]

VPN systems may be classified by:

The tunneling protocol used to tunnel the traffic

The tunnel's termination point location, e.g., on the customer edge or network-provider edge

The type of topology of connections, such as site-to-site or network-to-network

The levels of security provided

The OSI layer they present to the connecting network, such as Layer 2 circuits or Layer privat tunel vpn network connectivity

The number of simultaneous connections

Security mechanisms[edit]

VPNs cannot make online connections completely anonymous, but they can usually increase privacy and security.

Authentication[edit]

Tunnel endpoints must be authenticated before secure VPN tunnels can be established. User-created remote-access VPNs may use passwords, biometrics, two-factor authentication or other cryptographic methods.

Network-to-network tunnels often use passwords or digital certificates. They permanently store the key to allow the tunnel to establish automatically, without intervention from the administrator.

Routing[edit]

Tunneling protocols can operate in a point-to-pointnetwork topology that privat tunel vpn theoretically not be considered as a VPN, because a VPN by definition is expected to support arbitrary and changing sets of network nodes.

RFC 4026 generalized the following terms to cover L2 and L3 VPNs, but they were introduced in RFC 2547.[14] More information on the devices below can also be found in Lewis, Cisco Press.[15]

Customer (C) devices

A device that is privat tunel vpn a customer's network and not directly connected to the service provider's network.

C devices are not aware of the VPN.

Customer Edge device (CE)

A device at the edge of the customer's network which provides access to the PPVPN. Sometimes it is just a demarcation point between provider and customer responsibility. Other providers allow customers to configure it.

Provider edge device (PE)

A PE is a device, or set of devices, at the edge of the provider network which connects to customer networks through CE devices and presents the provider's view of the customer site.

PEs are aware of the VPNs that connect through them, and maintain VPN state.

Provider device (P)

A P device operates inside the provider's core network and does not directly interface to any customer endpoint. It might, for example, provide routing for many provider-operated tunnels that belong to different customers' PPVPNs.

While the P device is a key part of implementing PPVPNs, it is not itself VPN-aware and does not maintain VPN state. Its principal role is allowing the service provider privat tunel vpn scale its PPVPN offerings, for example, by acting as an aggregation point for multiple PEs.

P-to-P connections, in privat tunel vpn a role, often are high-capacity optical links between major locations of providers.

User-visible PPVPN services[edit]

OSI Layer 2 services[edit]

Virtual LAN

Virtual LAN (VLAN) is a Layer 2 technique that allow for the coexistence of multiple local area network (LAN) broadcast domains, interconnected via trunks using the IEEE 802.1Q trunking protocol.

Other trunking protocols have been used but have become obsolete, including Inter-Switch Link (ISL), IEEE 802.10 (originally a security protocol but a subset was introduced for trunking), and ATM LAN Emulation (LANE).

Virtual private LAN service (VPLS)

Developed by Institute of Electrical and Electronics Engineers, VLANs allow multiple tagged LANs to share common trunking. VLANs frequently comprise only customer-owned facilities.

Whereas VPLS as described in the above section (OSI Layer 1 services) supports emulation of both point-to-point and point-to-multipoint topologies, the method discussed here extends Layer 2 technologies such as 802.1d and 802.1q LAN trunking to run over transports such as Metro Ethernet.

As used in this context, a Privat tunel vpn is a Layer 2 PPVPN, rather than a private line, privat tunel vpn the full functionality of a traditional LAN.

From a user standpoint, a VPLS makes it possible to interconnect several LAN segments over a packet-switched, or optical, provider core; a core transparent to the user, making the remote LAN segments behave as one single LAN.[16]

In a VPLS, the provider network emulates a learning privat tunel vpn, which optionally may include VLAN privat tunel vpn wire (PW)

PW is similar to VPLS, but it can provide different L2 protocols at both ends.

Typically, its interface is a WAN protocol such as Asynchronous Transfer Mode or Frame Relay. In contrast, when aiming to provide the appearance of a LAN contiguous between two or more locations, the Virtual Private LAN service or IPLS would be appropriate.

Ethernet over IP tunneling

EtherIP (RFC 3378)[17] is an Ethernet over IP tunneling protocol specification. EtherIP has only packet encapsulation mechanism. It has no confidentiality nor message integrity protection.

EtherIP was introduced in the FreeBSD network stack[18] and the SoftEther VPN[19] server program.

IP-only LAN-like service (IPLS)

A subset of VPLS, the CE devices must have Layer privat tunel vpn capabilities; the IPLS presents packets rather than frames.

It may support IPv4 or IPv6.

OSI Layer 3 PPVPN architectures[edit]

This privat tunel vpn discusses the main architectures for PPVPNs, one where the PE disambiguates duplicate addresses in a single routing instance, and the other, virtual router, in which the PE contains a virtual privat tunel vpn instance per VPN.

The former approach, and its variants, have gained the most attention.

One of the challenges of PPVPNs involves different customers privat tunel vpn the same privat tunel vpn space, especially the IPv4 private address space.[20] The provider must be able to disambiguate overlapping addresses in the multiple customers' PPVPNs.

BGP/MPLS PPVPN

In the method defined by RFC 2547, BGP extensions advertise routes in the IPv4 VPN address family, privat tunel vpn are of the form of 12-byte strings, beginning with an 8-byte route distinguisher privat tunel vpn and ending with a 4-byte IPv4 address.

RDs disambiguate otherwise duplicate addresses in the same PE.

PEs understand the topology of each VPN, which are interconnected with MPLS tunnels, either directly or via P routers.

The virtual router architecture,[21][22] as opposed to BGP/MPLS techniques, requires no modification to existing routing protocols such as BGP.

By the provisioning of logically independent routing domains, the customer operating a VPN is completely responsible for the address space. In the various MPLS tunnels, the different PPVPNs are disambiguated by their label, but do not need routing distinguishers.

Unencrypted tunnels[edit]

Some virtual networks use tunneling protocols without encryption for protecting the privacy of data.

While VPNs often do provide privat tunel vpn, an unencrypted overlay network does not neatly fit within the secure or trusted categorization.[citation needed] For example, a tunnel set up between two hosts with Generic Routing Encapsulation (GRE) is a virtual private network, but neither secure nor trusted.[23][24]

Native plaintext tunneling protocols include Layer 2 Tunneling Protocol (L2TP) when it is set up without IPsec and Point-to-Point Tunneling Protocol (PPTP) or Microsoft Point-to-Point Encryption (MPPE).[25]

Trusted delivery networks[edit]

Trusted VPNs do not use cryptographic tunneling, and instead rely on the security of a single provider's network to protect the traffic.[26]

Multi-Protocol Label Switching (MPLS) often overlays VPNs, often with quality-of-service control over a trusted delivery network.

L2TP[27] which is a standards-based replacement, and a compromise taking the good features from each, for two proprietary VPN protocols: Cisco's Layer 2 Forwarding (L2F)[28] (obsolete as of 2009[update]) and Microsoft's Point-to-Point Tunneling Protocol (PPTP).[29]

From the security standpoint, VPNs privat tunel vpn trust the privat tunel vpn delivery network, or must enforce security with mechanisms in the VPN itself.

VPNs in mobile environments[edit]

Mobile virtual private networks are used in settings where an endpoint of the VPN is not fixed to a single IP address, but instead roams across various networks such as data networks from cellular carriers or between multiple Wi-Fi access points.[30] Mobile VPNs have been widely privat tunel vpn in public safety, where they give law enforcement officers access to mission-critical applications, such as computer-assisted dispatch and criminal databases, while they travel between different subnets of a mobile network.[31] They are also used in field service management and by healthcare organizations,[32] among other industries.

Increasingly, mobile VPNs are being adopted by mobile professionals who need reliable connections.[32] They are used for roaming seamlessly across networks and in and out of wireless coverage areas without privat tunel vpn application sessions or dropping the secure VPN session.

A conventional VPN can not withstand such events because the network tunnel is disrupted, causing applications to disconnect, time out,[30] or fail, or even cause the computing device itself to crash.[32]

Instead of logically tying the endpoint of the network tunnel to the physical IP address, each tunnel is bound to a permanently associated IP address at the device.

The mobile VPN software handles the necessary network authentication and maintains the network sessions in a manner transparent to the application and the user.[30] The Host Identity Protocol (HIP), under study by the Internet Engineering Task Force, is designed to support mobility of hosts by separating the role of IP addresses for host identification from their locator functionality in an IP network.

With HIP a mobile host maintains its logical connections established via the host identity identifier while associating with different IP addresses when roaming between access networks.

VPN on routers[edit]

With the increasing use of VPNs, many have started deploying VPN connectivity on routers for additional security and encryption of data transmission by using various cryptographic techniques.[33] Home users usually deploy VPNs on their routers to protect devices, such as smart TVs or gaming consoles, which are not supported by native VPN clients.

Supported devices are not restricted to those capable of running a VPN client.[34]

Many router manufacturers supply routers with built-in VPN clients. Some use open-source firmware such as DD-WRT, OpenWRT and Tomato, in order to support additional protocols such as OpenVPN.

Networking limitations[edit]

One major limitation of traditional VPNs is that they are point-to-point, and do not tend to support or connect broadcast domains.

Privat tunel vpn, communication, software, and networking, which are based on layer 2 and broadcast packets, such as NetBIOS used in Windows networking, may not be fully supported or work exactly as they would on a real LAN. Variants on VPN, such as Virtual Private LAN Service (VPLS), and layer 2 tunneling protocols, are designed to overcome this limitation.[citation needed]